1. Field of Invention
The invention relates to photographic cameras having adjustable exposure and focus settings, and more specifically to a mechanism in such cameras for focusing an optical element and setting a maximum aperture.
2. Description of the Prior Art
Camera mechanisms for adjusting focus and exposure come in many varieties. Those considered most pertinent to the present invention use an actuating member that rotates in a first direction for setting focus and a second opposite direction for controlling exposure. Typically, focus is established first by cams that rotate with the member in the first direction against ramps on an optical element, moving it axially into focus. The focusing components then are held stationary while the shutter is actuated by rotation of the member in the opposite direction. The shutter usually includes blades that move in a timed sequence controlled by movement of the actuating member, and the maximum aperture depends on the time period of the blade opening part of the sequence.